#include "mystdio.h"

mFILE *mfopen(const char *filename, const char *mode)
{
    int fd = -1;
	if (strcmp(mode, "r") == 0)
	{
		fd = open(filename, O_RDONLY);
	}
	else if (strcmp(mode, "w") == 0)
	{
		fd = open(filename, O_CREAT | O_WRONLY | O_TRUNC, 0666);
	}
	else if (strcmp(mode, "a") == 0)
	{
		fd = open(filename, O_CREAT | O_WRONLY | O_APPEND, 0666);
	}
	if (fd < 0)
	{
		return NULL;
	}
	mFILE *mf = (mFILE*)malloc(sizeof(mFILE));
	if (mf == NULL)
	{
		close(fd);
		return NULL;
	}

	mf->flag = FLUSH_LINE;
	mf->fileno = fd;
	mf->size = 0;
	mf->capacity = SIZE;

	return mf;
}

void mfflush(mFILE *stream)
{
	if (stream->size > 0)
	{
		//刷新的本质
		write(stream->fileno, stream->outbuffer, stream->size);
		stream->size = 0;
	}
}

int mfwrite(const void *ptr, int num, mFILE *stream)
{
	//1、库函数写方法：将数据拷贝到缓冲区
	memcpy(stream->outbuffer+stream->size, ptr, num);
	stream->size += num;

	//2、检测是否刷新
	if (stream->flag == FLUSH_LINE && stream->size > 0 && stream->outbuffer[stream->size - 1] == '\n')
	{
		mfflush(stream);
	}
	return num;
}

void mfclose(mFILE *stream)
{
	if (stream->size > 0)
	{
		mfflush(stream);
	}
	close(stream->fileno);
}

